Almost as soon as we were through 10,000 feet, I had my atlas out. It was completely clear along our route - a rarity in November - and on the dark, moonless night, every light for hundreds of miles was visible. Every town and road printed on the map was duplicated in orange and white pixels below. From Memphis we headed northeastwards on J42, toward Nashville. It grew steadily brighter until we passed overhead; then the glow of suburbia quickly gave way to the isolated pinpricks of eastern Kentucky's rural hill country. Louisville floated by to our left; to our right, Knoxville illuminated the spine of the Great Smokey Mountains. My First Officer broke the silence to point out his hometown where Tennessee, Kentucky, and Virginia all come together. At Beckley, WV, we made a slight right to cross the Ridge-and-Valley Appalachians just north of I-64. A thin band of light stretching as far as the eye could see marked the Great Valley; the dark band after that, the Blue Ridge. We reentered "civilization" over Charlottesville, VA, the pixels becoming ever thicker and brighter as we approached Washington DC. From 35,000 feet, we could clearly make out the dark National Mall and the floodlit Capitol Building. As we passed over Chesapeake Bay into Delaware, I noted how Washington, Baltimore, Philadelphia, Newark, and New York essentially form one contiguous, enormous metropolis. The Jersey shore, to our right, was much darker but the casinos of Atlantic City shone brightly, prompting my FO to reminisce about his freight dog days flying into ACY. Now New York's glow, visible 200 miles prior, hardened and formed into city and water, then the individual boroughs, and then mile after mile of individual streets and buildings. I picked out the Empire State and Chrysler Buildings as we overflew JFK and LGA. At the Connecticut coast we turned right; the moonless night and dark waters of Long Island Sound made me think of JFK, Jr. By now we were on our descent; the arrival took us over Providence, RI, which until then had always been a fuzzy spot in my geographical knowledge. We went "feet wet" above the spot that the Pilgrims went "feet dry." The vectors to final took us far out over the Atlantic, almost to the tip of Cape Cod. Our 150 minute night tour of the east coast concluded with a nice view of the Boston skyline from the final approach to runway 27.
Prior to flying for NewCo, I had spent very little time "out east." In fact, the furthest east I'd flown was Grand Rapids, MI, and that was on a cross-country flight I did in college! My subsequent flight instructing, freight dogging, and airline flying was all on the west coast. At Horizon, the easternmost destination for the Q400 was Billings, MT. At NewCo, the majority of our destinations are east of the Mississippi. On the east coast proper, we fly to MHT, BOS, JFK, LGA, EWR, PHL, BWI, IAD, RIC, ORF, CLT, JAX, and MCO. When I began flying to these places, my geographic knowledge was sorely lacking. Now all the pieces are starting to fit together.
When I was flying out west, I had no idea just how good I had it. Flying on the east coast in a royal pain. Out west, it's Direct-To everywhere and talk to ATC once every 20 minutes to change frequencies. Out east, it's nonstop convoluted reroutes, last-minute crossing altitude restrictions, and an endless litany of frequency changes. You eventually give up even trying to check in with certain sectors after having your check in stepped on half a dozen times. Airports like PHL, EWR, LGA, and JFK are delay-prone on good days; throw in some bad weather and you're going nowhere quick. Those airports make me thankful that our turd of a contract at least has "Block or Better" pay.* Our hotels at eastern layovers tend to be in decrepit industrial areas near the airport, and the shuttle van drivers are often surly and hurried.
Despite all that, I still enjoy going east. I guess the novelty just hasn't worn off yet. I enjoy the aerial sightseeing when the weather cooperates. The Appalachians, Catskills, and Adirondacks, while less starkly grand than the Rockies, Sierras, and Cascades, have great natural beauty of their own. The human geography, too, is interesting to me: the patchwork quilt-like farmsteads of rural areas, the little towns secluded in dead-end valleys miles from anywhere, the seemingly endless cities of the BosWash corridor. There's a lot of history out east; I enjoy having a birds-eye view of the landscape that famous battles and campaigns were waged across.
On the ground, there's a lot to do if you make the effort. I haven't spent much time in most of the cities we go to, so they invite exploration. The morning after my sightseeing flight up the eastern seaboard, I woke up early and hopped on the subway to downtown Boston. I reemerged at Boston Common, America's oldest park, and started following the red brick path of the Freedom Trail. It was fascinating to see so many important historical sites in the course of a fairly short stroll. The South Meeting House, the Old State House, Old North Church, and Bunker Hill are all legendary places I've heard about since grade school but have never seen for myself. Walking in and around them made the history seem more real, more palpable; I felt new appreciation for the vision and courage of men like Joseph Warren, Samuel Adams, and Paul Revere.
I have a long Philadelphia layover coming up soon. I hope to make it to the Revolution-era sights there. If they're anywhere nearly as interesting as the Freedom Trail in Boston, it should take some of the sting out of having to operate out of PHL.
*"Block or Better" means that we are paid the greater of scheduled or actual block time. Therefore, when we're delayed we get paid extra, but we don't get shorted for being early. Although Horizon has a much better contract than NewCo, they did not have Block or Better; I got paid based only on the historical block time for the leg (usually less than scheduled block), with no additional compensation for overblocking. If Horizon flew into JFK, LGA, or PHL, that'd be a very bad thing to have in the contract.
Sunday, November 30, 2008
Friday, November 21, 2008
The Iceman Cometh
Well, there's no escaping it now. Minnesota has had several days of snow, although none of it lasted more than a few hours; it's currently 12 degrees in Minneapolis. When I got done with a trip yesterday morning, my short walk from the bus stop to our apartment froze my fingers and ears so thoroughly that I didn't venture outside again all day. My six month hibernation begins now.
If I could spend the entire winter curled up inside with a warm blanket and hot chocolate I very possibly would, but alas, the need to earn a living saves me from being a total recluse during winter. Being a pilot is a good job for someone who hates long cold winters but lives in Minnesota, as it gets me above the clouds into sunshine rather frequently and also involves the occasional layover in Phoenix or San Antonio. Unfortunately two of RedCo's three hubs are in northern states, so I do spend a lot of time operating in wintry conditions. This rather frequently involves deicing. I deiced for the first time of the season about a month ago. Given that I hadn't done it since last winter, I took that as my cue to open our Deicing/Anti-icing manual and study up.
As I mentioned in my last post, anti-icing systems on jets are beautifully effective in flight but provide no protection on the ground. For that, we use propylene glycol-based deicing fluids somewhat similar to the antifreeze fluid used in your car. Similar fluids have been used in aviation for quite a while, but for a long time they were poorly understood and their use was nonstandard throughout the industry. After some notable accidents involving airliners attempting takeoff with iced-up wings, the FAA got serious about ground deicing. Now every Part 121 carrier is required to maintain and distribute an FAA-approved Ground Deicing/Anti-icing Manual. It spells out in great detail the various ground and flight crew roles and responsibilities, what parts of the aircraft must be "clean" for takeoff, approved methods of removing contamination, the limitations of various anti-ice fluids, and the checks that must be accomplished before an airplane may take off.
As the name of the manual suggests, there are two stages to ground deicing/anti-icing. Deicing is intended to remove any previously accumulated contaminants that are adhering to the airframe. This may include frost, freezing rain, snow, or airframe ice from the last flight. Anti-icing prevents further accumulation of freezing precipitation between deicing and takeoff. In very mild conditions, both of these steps may be accomplished in a single application of deicing fluid, but more often the steps are accomplished with separate coats of different fluids.
The deice fluid used to remove previous contaminants is called Type I fluid. It is fairly thin, slippery, and is dyed red to help deicing personnel see which parts of the aircraft have already been sprayed. Type I fluid is normally heated between 130 and 180 degrees F, and is sprayed out at considerable pressure to aid in knocking contaminants off the airframe. As Type I fluid isn't very viscous, it doesn't adhere to the airframe well. It also has a somewhat limited ability to absorb moisture. For both of these reasons, Type I fluid is used for anti-icing purposes only for short periods or in very light ground icing conditions.
The more commonly used anti-ice fluid is called Type IV. It has thickening agents added and is dyed green. Type IV is always applied cold after a previous application of Type I fluid. It is sometimes diluted with water, not only to save costs but also to (rather counter-intuitively) lower its freezing point. A solution of 75% fluid and 25% water has a freezing point of around -55C; undiluted fluid has around the same -30C freezing point as a 50-50 mix. Type IV fluid's greater viscosity helps it to better adhere to the airframe. It is designed to shear off at around 100 knots airspeed on the takeoff roll, leaving a clean wing. It also has greater moisture absorption capabilities than Type I fluid. All this means that it protects the airframe against contamination for much longer periods than Type I fluid.
The most common apparatus used to spray deicing fluid is a boom truck. The truck drives around the aircraft while the deicer sprays the fluid from a basket on top of the boom. Both Type I and Type IV fluid can be and often are sprayed from the same truck in subsequent applications. A fairly recent development is infrared deicing. Infrared deicers melt existing snow and ice off the airframe as the plane taxies through a hangar-like structure. This arrangement still requires a truck to spray Type IV fluid for anti-ice protection. There are only a few infrared deice installations in the US.
Occasionally ground crews will deice aircraft before the flight crew arrives in the morning if there was frost or snow accumulation overnight but ground icing no longer exists. Usually, though, crews must request deicing. At small stations, the ground crew needs advance warning to make sure the truck has enough fluid and to heat it up. If there are any contaminants adhering to the airframe, or if there's steady snowfall, the decision to deice is an easy one. It's less clear when the temperatures are just warm enough that the snow is melting on contact, or if flurries aren't quite sticking to the airframe. You don't want to deice unnecessarily due to the time and cost involved, but you also don't want changing conditions to make you come back for deicing at the last minute either.
At outstations, I'll inform operations or a member of the ground crew that we need to deice at least 30 minutes before departure. At most of these airports, we get deiced right after pushback from our gate, before we've started our engines. At the smallest stations, the same rampers that just loaded the bags and pushed us back will then hop in the deice truck. At large northern outstations and hub airports, there are dedicated deice pads located near the end of the runways and manned by a virtual army of trucks and staff during winter weather. At Minneapolis, there are four deice pads that can each handle half a dozen aircraft simultaneously! The usual drill is to call "The Iceman," or central coordinator, as soon as you know you'll need deicing. They'll either assign you a pad or dispatch a truck to deice you near the gate when you push back. If assigned a pad, you confirm it with the Iceman when you begin taxiing and then contact that pad on a discrete frequency to be assigned a lane. You usually deice with engines running at deice pads.
Before the crew begins deicing, the deice coordinator will plug into the ground intercom or transmit via radio to confirm what type of fluid we want and that we are configured for deice. This involves ensuring the flaps are retracted, the stabilizer trim is full nose-down (to prevent fluid from entering internal mechanisms), and turning off all the bleed and pack switches. This last step is especially important to prevent passengers from breathing atomized glycol. Unlike ethylene glycol (antifreeze), propylene glycol is supposed to be fairly non-toxic - but it's not exactly pleasant to inhale, either. After deicing is complete, we wait a full minute before selecting bleed sources on, and another minute after that before turning the packs back on.
Once the process is complete, the deice coordinator will tell us the type and amount of fluid used, the fluid/water mixture and freezing point, and the time that fluid application began. The last bit of information is especially important, for it is the time that our holdover time is calculated from. Holdover time is the length of time that the fluid can be expected to provide anti-ice protection in active ground icing conditions. It varies by type and mix of fluid, type and intensity of precipitation, outside air temperature, and a few other factors. We use a series of tables to calculate our holdover time for the given conditions. The tables give us a range of times; for example, with moderate snowfall at a temperature of -5C, Type I fluid has a holdover time of five to eight minutes and undiluted Type IV has a holdover time of 20 to 40 minutes. The Captain chooses a holdover time within this range that most closely corresponds to prevailing conditions, and may adjust the time upward or downward in response to changing conditions. The holdover time begins when the application of the last coat of anti-ice fluid begins; takeoff must be commenced before the holdover time expires.
Of course, in any weather that makes holdover time a factor, there are likely air traffic delays that may hinder a timely takeoff. ATC is usually pretty good about asking pilots their holdover expiration and resequencing aircraft if necessary. Sometimes best efforts aren't enough and the holdover time expires. Different airlines handle this in different ways. Some require the aircraft to return for secondary deicing. Others, including NewCo, permit the use of a Pre-Takeoff Contamination Check. This is a tactile exterior inspection conducted by trained deicing personnel to confirm that the aircraft is still clean and the fluid has not failed. If the aircraft passes this check, it is still allowed to take off so long as the takeoff happens within five minutes of the check. Close coordination between the crew and operations is necessary to ensure there are personnel available at the end of the runway in case holdover time expires.
In any case, shortly before takeoff the flight crew must perform their own Pre-Takeoff Check to ensure the fluid has not become saturated with moisture. Basically you just look at the few airframe parts visible from the cockpit and observe the sheen of the fluid. If it is dull and milky, the fluid has failed and the aircraft must be deiced again. If it's still glossy, then you're set to go. Hopefully you're headed South where you can thaw a bit. Unless they're having a cold snap, that is; the only thing worse than winter weather in the North is winter weather in the South! While Minneapolis and Detroit are true pros at fast, effective deicing, the same is decidedly not true of places that only see winter weather once or twice a year. They simply aren't equipped or staffed for it, and there's always a learning curve.
Portland is one notable exception. They're blessed with fairly mild winter weather but when they do get it, it's in the form of truly nasty ice storms. Accordingly, Horizon puts heavy emphasis on training and equipping their PDX deicing crews for those days. In the end, it's usually all for naught; they soldier on for a few hours before freezing rain closes the airport entirely and grounds a large portion of Horizon's fleet. A few years ago a friend of mine was the FO on the last flight that landed before a particularly nasty ice storm closed PDX for several days. In the last few minutes of the flight, they encountered heavy freezing rain; by the time they landed, every inch of the airframe was encrusted in several inches of ice! The deicing team's last act before conceding to Mother Nature was to deice my friend's CRJ so they could get the main cabin door open to deplane the passengers.
If I could spend the entire winter curled up inside with a warm blanket and hot chocolate I very possibly would, but alas, the need to earn a living saves me from being a total recluse during winter. Being a pilot is a good job for someone who hates long cold winters but lives in Minnesota, as it gets me above the clouds into sunshine rather frequently and also involves the occasional layover in Phoenix or San Antonio. Unfortunately two of RedCo's three hubs are in northern states, so I do spend a lot of time operating in wintry conditions. This rather frequently involves deicing. I deiced for the first time of the season about a month ago. Given that I hadn't done it since last winter, I took that as my cue to open our Deicing/Anti-icing manual and study up.
As I mentioned in my last post, anti-icing systems on jets are beautifully effective in flight but provide no protection on the ground. For that, we use propylene glycol-based deicing fluids somewhat similar to the antifreeze fluid used in your car. Similar fluids have been used in aviation for quite a while, but for a long time they were poorly understood and their use was nonstandard throughout the industry. After some notable accidents involving airliners attempting takeoff with iced-up wings, the FAA got serious about ground deicing. Now every Part 121 carrier is required to maintain and distribute an FAA-approved Ground Deicing/Anti-icing Manual. It spells out in great detail the various ground and flight crew roles and responsibilities, what parts of the aircraft must be "clean" for takeoff, approved methods of removing contamination, the limitations of various anti-ice fluids, and the checks that must be accomplished before an airplane may take off.
As the name of the manual suggests, there are two stages to ground deicing/anti-icing. Deicing is intended to remove any previously accumulated contaminants that are adhering to the airframe. This may include frost, freezing rain, snow, or airframe ice from the last flight. Anti-icing prevents further accumulation of freezing precipitation between deicing and takeoff. In very mild conditions, both of these steps may be accomplished in a single application of deicing fluid, but more often the steps are accomplished with separate coats of different fluids.
The deice fluid used to remove previous contaminants is called Type I fluid. It is fairly thin, slippery, and is dyed red to help deicing personnel see which parts of the aircraft have already been sprayed. Type I fluid is normally heated between 130 and 180 degrees F, and is sprayed out at considerable pressure to aid in knocking contaminants off the airframe. As Type I fluid isn't very viscous, it doesn't adhere to the airframe well. It also has a somewhat limited ability to absorb moisture. For both of these reasons, Type I fluid is used for anti-icing purposes only for short periods or in very light ground icing conditions.
The more commonly used anti-ice fluid is called Type IV. It has thickening agents added and is dyed green. Type IV is always applied cold after a previous application of Type I fluid. It is sometimes diluted with water, not only to save costs but also to (rather counter-intuitively) lower its freezing point. A solution of 75% fluid and 25% water has a freezing point of around -55C; undiluted fluid has around the same -30C freezing point as a 50-50 mix. Type IV fluid's greater viscosity helps it to better adhere to the airframe. It is designed to shear off at around 100 knots airspeed on the takeoff roll, leaving a clean wing. It also has greater moisture absorption capabilities than Type I fluid. All this means that it protects the airframe against contamination for much longer periods than Type I fluid.
The most common apparatus used to spray deicing fluid is a boom truck. The truck drives around the aircraft while the deicer sprays the fluid from a basket on top of the boom. Both Type I and Type IV fluid can be and often are sprayed from the same truck in subsequent applications. A fairly recent development is infrared deicing. Infrared deicers melt existing snow and ice off the airframe as the plane taxies through a hangar-like structure. This arrangement still requires a truck to spray Type IV fluid for anti-ice protection. There are only a few infrared deice installations in the US.
Occasionally ground crews will deice aircraft before the flight crew arrives in the morning if there was frost or snow accumulation overnight but ground icing no longer exists. Usually, though, crews must request deicing. At small stations, the ground crew needs advance warning to make sure the truck has enough fluid and to heat it up. If there are any contaminants adhering to the airframe, or if there's steady snowfall, the decision to deice is an easy one. It's less clear when the temperatures are just warm enough that the snow is melting on contact, or if flurries aren't quite sticking to the airframe. You don't want to deice unnecessarily due to the time and cost involved, but you also don't want changing conditions to make you come back for deicing at the last minute either.
At outstations, I'll inform operations or a member of the ground crew that we need to deice at least 30 minutes before departure. At most of these airports, we get deiced right after pushback from our gate, before we've started our engines. At the smallest stations, the same rampers that just loaded the bags and pushed us back will then hop in the deice truck. At large northern outstations and hub airports, there are dedicated deice pads located near the end of the runways and manned by a virtual army of trucks and staff during winter weather. At Minneapolis, there are four deice pads that can each handle half a dozen aircraft simultaneously! The usual drill is to call "The Iceman," or central coordinator, as soon as you know you'll need deicing. They'll either assign you a pad or dispatch a truck to deice you near the gate when you push back. If assigned a pad, you confirm it with the Iceman when you begin taxiing and then contact that pad on a discrete frequency to be assigned a lane. You usually deice with engines running at deice pads.
Before the crew begins deicing, the deice coordinator will plug into the ground intercom or transmit via radio to confirm what type of fluid we want and that we are configured for deice. This involves ensuring the flaps are retracted, the stabilizer trim is full nose-down (to prevent fluid from entering internal mechanisms), and turning off all the bleed and pack switches. This last step is especially important to prevent passengers from breathing atomized glycol. Unlike ethylene glycol (antifreeze), propylene glycol is supposed to be fairly non-toxic - but it's not exactly pleasant to inhale, either. After deicing is complete, we wait a full minute before selecting bleed sources on, and another minute after that before turning the packs back on.
Once the process is complete, the deice coordinator will tell us the type and amount of fluid used, the fluid/water mixture and freezing point, and the time that fluid application began. The last bit of information is especially important, for it is the time that our holdover time is calculated from. Holdover time is the length of time that the fluid can be expected to provide anti-ice protection in active ground icing conditions. It varies by type and mix of fluid, type and intensity of precipitation, outside air temperature, and a few other factors. We use a series of tables to calculate our holdover time for the given conditions. The tables give us a range of times; for example, with moderate snowfall at a temperature of -5C, Type I fluid has a holdover time of five to eight minutes and undiluted Type IV has a holdover time of 20 to 40 minutes. The Captain chooses a holdover time within this range that most closely corresponds to prevailing conditions, and may adjust the time upward or downward in response to changing conditions. The holdover time begins when the application of the last coat of anti-ice fluid begins; takeoff must be commenced before the holdover time expires.
Of course, in any weather that makes holdover time a factor, there are likely air traffic delays that may hinder a timely takeoff. ATC is usually pretty good about asking pilots their holdover expiration and resequencing aircraft if necessary. Sometimes best efforts aren't enough and the holdover time expires. Different airlines handle this in different ways. Some require the aircraft to return for secondary deicing. Others, including NewCo, permit the use of a Pre-Takeoff Contamination Check. This is a tactile exterior inspection conducted by trained deicing personnel to confirm that the aircraft is still clean and the fluid has not failed. If the aircraft passes this check, it is still allowed to take off so long as the takeoff happens within five minutes of the check. Close coordination between the crew and operations is necessary to ensure there are personnel available at the end of the runway in case holdover time expires.
In any case, shortly before takeoff the flight crew must perform their own Pre-Takeoff Check to ensure the fluid has not become saturated with moisture. Basically you just look at the few airframe parts visible from the cockpit and observe the sheen of the fluid. If it is dull and milky, the fluid has failed and the aircraft must be deiced again. If it's still glossy, then you're set to go. Hopefully you're headed South where you can thaw a bit. Unless they're having a cold snap, that is; the only thing worse than winter weather in the North is winter weather in the South! While Minneapolis and Detroit are true pros at fast, effective deicing, the same is decidedly not true of places that only see winter weather once or twice a year. They simply aren't equipped or staffed for it, and there's always a learning curve.
Portland is one notable exception. They're blessed with fairly mild winter weather but when they do get it, it's in the form of truly nasty ice storms. Accordingly, Horizon puts heavy emphasis on training and equipping their PDX deicing crews for those days. In the end, it's usually all for naught; they soldier on for a few hours before freezing rain closes the airport entirely and grounds a large portion of Horizon's fleet. A few years ago a friend of mine was the FO on the last flight that landed before a particularly nasty ice storm closed PDX for several days. In the last few minutes of the flight, they encountered heavy freezing rain; by the time they landed, every inch of the airframe was encrusted in several inches of ice! The deicing team's last act before conceding to Mother Nature was to deice my friend's CRJ so they could get the main cabin door open to deplane the passengers.
Thursday, November 06, 2008
JungleBus Systems Post: Ice Protection
I recently had a passenger stop at the flight deck during deplaning to say hi to me and the FO. It turned out that he's a Private Pilot with an instrument rating, and flies a nearly-new Cessna 172 with a Garmin G1000 glass cockpit, traffic information system, and weather datalink. We marveled at the advances in general aviation avionics the past few years, and I remarked to him that his cockpit was as sophisticated as ours for a mere fraction of the cost. "Yeah," he said wistfully, "but it's still a single-engine piston, and despite all the goodies I still can't fly it half the winter."
It's a good point. Advanced avionics have brought light aircraft up to transport category standards in many respects and greatly improved their usefulness, but icing remains a significant problem for light aircraft. Despite some advances in technology to make anti-ice equipment lighter and cheaper, only some light twins and very few singles are approved for flight into known icing. A lot of the equipment is of dubious effectiveness, and prudent pilots don't remain in icing conditions for long even in "known ice" airplanes. Transport category jets, on the other hand, have had icing pretty well licked for over 40 years. This is in large part due to their superior performance: icing conditions tend to be pretty localized both by area and altitude, so aircraft with plenty of speed and power can blow through icing too quick for it to be much of a problem. Icing at cruise altitudes is rare for jets; the air is usually too cold to support enough moisture for significant icing. Jets have a significant advantage in the equipment department, too. They enjoy a steady supply of hot air from their engines' bleed valves, which is used to heat the wings, tail, and engine inlets. It's been an effective system since its inception, and has been adapted on most jet aircraft from the DC-8 until today - although the B787 will soon be a notable exception.
The JungleBus is no exception. Its ice protection equipment is pretty standard for a jet, although the operation is more automated than most aircraft. The leading edges of the wings are heated by bleed air via the pneumatic system; the engine intakes are heated by air that comes directly from the 10th stage compressor bleed. Both vertical and horizontal stabilizers are unheated; this is noteworthy but not unprecedented. The manufacturer had to prove during certification tests that the aircraft was not prone to tailplane stall or control problems with unusually heavy ice accumulation on the tail. I know - I'm not utterly convinced, either. The remainder of the anti-ice system is electric; protected areas include both windshields, the Air Data Smart Probes (pitot/static/AOA) and True Air Temperature (TAT) probes.
A key difference between hot-wing anti-ice systems on jets and the inflatable rubber de-ice boots used on smaller aircraft is when they should be turned on. Despite some controversy on the subject, most pilots still wait to inflate their de-ice boots until there has been some accumulation of ice. Anti-ice systems, however, must be turned on at the first sign of icing (or before). You don't want ice to build up on the cowl inlet only to be ingested into the engine when the cowl is heated; it can do a lot of damage to the compressor blades. Likewise, applying heat to a wing leading edge that already has a significant accumulation of ice can cause it to melt and refreeze further aft on the unprotected portion of the wing. Because it's hard to see the wing tips on most swept-wing airplanes, you have to rely on other cues to know when you've started accumulating ice. The windshield wiper often accumulates ice before any other part and makes for a good visual first warning. Transport category aircraft are also required to be equipped with ice detectors. These ingenious devices are metal rods that protrude from the nose of the aircraft which are vibrated at a particular frequency. Any ice accumulation will change the frequency of the vibrations, triggering an icing warning in the cockpit. Occasionally the detectors are heated to knock off existing ice so they can determine whether icing conditions still exist.
On most aircraft, the various icing systems must be turned on manually. Most operators direct their pilots to do so when entering potential icing conditions (clouds or visible moisture near or below freezing temps), or at the latest when the ice detector gives an icing indication. This is where the JungleBus departs significantly from previous designs; it makes normal operation of all anti-ice systems fully automatic. The ice protection panel is a collection of dusty switches that rarely get touched; so long as the mode selector remains in AUTO, the system will automatically turn on wing and engine anti-ice whenever the ice detectors sense icing conditions from shortly after takeoff until landing. Meanwhile the windshields are protected any time there are at least two sources of AC electrical power, and the probes are heated automatically whenever an engine is running or manually via a button on the FO's main panel.
There is some manual control of the system for abnormal operations and for takeoff. Although the mode selector is normally left on AUTO, turning it to ON manually activates engine and wing anti-ice (on engine start and liftoff, respectively). Individual selector buttons for the wings, each engine, and each windshield allow each component to be manually deactivated. These are seldom used except when components fail. Manual control of anti-ice systems for takeoff via the Flight Management System is much more common. Using bleed air robs the engine of compressed air for combustion and therefore use of wing and engine anti-ice results in decreased power output. For this reason, the JungleBus inhibits automatic operation of both wing and engine anti-ice until reaching 1700 feet AGL after takeoff. If anti-ice protection is desired for takeoff, the pilots must set it on the Takeoff Dataset Page of the Multi-Function Control Display Unit (MCDU, otherwise known as the FMS head). The standard mode, which inhibits anti-ice until 1700 feet AGL, is OFF. Turning it to ENG mode turns on engine anti-ice as soon as the engine is started. The ALL mode enables engine anti-ice on engine start and wing anti-ice when wheel speed exceeds 40 knots on takeoff. In both cases, the anti-ice systems revert to automatic operation once the plane reaches 1700 feet AGL.
At NewCo we turn the dataset to ENG mode if there is any precipitation falling or any surface contamination with a static air temperature of less than 10 degrees C, and we use ALL mode if there is visible moisture below 1700' AGL with a SAT of less than 5 degrees C. Of course we won't get any wing protection until achieving 40 knots on takeoff, so any prior contamination must be removed with de-ice fluid (Type I). This provides limited protection for active icing conditions on the ground (ie falling snow) so in many cases we follow application of de-ice fluid with a second coat of anti-ice fluid (Type IV). This is designed to absorb the falling precipitation and then shear off the wing during the takeoff roll, at which point the aircraft's own anti-ice systems will be protecting it.
Like most aircraft systems on the JungleBus, there is a dedicated synoptic page for the anti-ice system on the Multi Function Display (MFD). It displays the status of the bleed and anti-ice valves, pneumatic system pressures, and bleed air & wing duct temperatures. A color-coded schematic of the system makes it easier to quickly understand any abnormal conditions.
One annoyance of the JungleBus' ice protection system is that the ice detectors interact with the Stall Protection System with no provision for pilot intervention. Once ice is detected, the SPS will assume it remains on the airframe for the remainder of the flight and increase stick shaker & pusher speeds accordingly. This forces the pilots to use faster approach and landing speeds, which would be the correct thing to do anyways if the aircraft was actually loaded up with ice. It is, however, pretty ridiculous to be forced into using ice speeds to land in Dallas on a 90 degree day just because you picked up a trace of ice on climbout from Minneapolis several hours ago.
All in all, though, the JungleBus' ice protection system works pretty well. Last winter I had a few occasions where the ice built up pretty good on the windshield wiper before landing, and post-flight inspection revealed significant accumulation on unprotected surfaces but the heated portions of the wings and cowls remained absolutely clean. The aircraft handled quite well despite having a decent amount of ice on the nose, wing roots, and (gulp) tail. Really, the JungleBus' best ice-fighting technology is its thrust-to-weight ratio. Although transport category aircraft do have better equipment for dealing with ice than light aircraft, prudent airline pilots use it the same way as prudent private pilots: to keep ice accretion to minimum while exiting icing conditions ASAP. Being able to climb rapidly through icing layers means that the JungleBus' good ice protection comes in handy primarily when you find yourself stuck at a bad icing altitude for several minutes on approach.
We're supposed to get snow tonight so I think it won't be long before I put this knowledge to practical use. In my next post, I'll delve more deeply into de-icing ground procedures.
It's a good point. Advanced avionics have brought light aircraft up to transport category standards in many respects and greatly improved their usefulness, but icing remains a significant problem for light aircraft. Despite some advances in technology to make anti-ice equipment lighter and cheaper, only some light twins and very few singles are approved for flight into known icing. A lot of the equipment is of dubious effectiveness, and prudent pilots don't remain in icing conditions for long even in "known ice" airplanes. Transport category jets, on the other hand, have had icing pretty well licked for over 40 years. This is in large part due to their superior performance: icing conditions tend to be pretty localized both by area and altitude, so aircraft with plenty of speed and power can blow through icing too quick for it to be much of a problem. Icing at cruise altitudes is rare for jets; the air is usually too cold to support enough moisture for significant icing. Jets have a significant advantage in the equipment department, too. They enjoy a steady supply of hot air from their engines' bleed valves, which is used to heat the wings, tail, and engine inlets. It's been an effective system since its inception, and has been adapted on most jet aircraft from the DC-8 until today - although the B787 will soon be a notable exception.
The JungleBus is no exception. Its ice protection equipment is pretty standard for a jet, although the operation is more automated than most aircraft. The leading edges of the wings are heated by bleed air via the pneumatic system; the engine intakes are heated by air that comes directly from the 10th stage compressor bleed. Both vertical and horizontal stabilizers are unheated; this is noteworthy but not unprecedented. The manufacturer had to prove during certification tests that the aircraft was not prone to tailplane stall or control problems with unusually heavy ice accumulation on the tail. I know - I'm not utterly convinced, either. The remainder of the anti-ice system is electric; protected areas include both windshields, the Air Data Smart Probes (pitot/static/AOA) and True Air Temperature (TAT) probes.
A key difference between hot-wing anti-ice systems on jets and the inflatable rubber de-ice boots used on smaller aircraft is when they should be turned on. Despite some controversy on the subject, most pilots still wait to inflate their de-ice boots until there has been some accumulation of ice. Anti-ice systems, however, must be turned on at the first sign of icing (or before). You don't want ice to build up on the cowl inlet only to be ingested into the engine when the cowl is heated; it can do a lot of damage to the compressor blades. Likewise, applying heat to a wing leading edge that already has a significant accumulation of ice can cause it to melt and refreeze further aft on the unprotected portion of the wing. Because it's hard to see the wing tips on most swept-wing airplanes, you have to rely on other cues to know when you've started accumulating ice. The windshield wiper often accumulates ice before any other part and makes for a good visual first warning. Transport category aircraft are also required to be equipped with ice detectors. These ingenious devices are metal rods that protrude from the nose of the aircraft which are vibrated at a particular frequency. Any ice accumulation will change the frequency of the vibrations, triggering an icing warning in the cockpit. Occasionally the detectors are heated to knock off existing ice so they can determine whether icing conditions still exist.
On most aircraft, the various icing systems must be turned on manually. Most operators direct their pilots to do so when entering potential icing conditions (clouds or visible moisture near or below freezing temps), or at the latest when the ice detector gives an icing indication. This is where the JungleBus departs significantly from previous designs; it makes normal operation of all anti-ice systems fully automatic. The ice protection panel is a collection of dusty switches that rarely get touched; so long as the mode selector remains in AUTO, the system will automatically turn on wing and engine anti-ice whenever the ice detectors sense icing conditions from shortly after takeoff until landing. Meanwhile the windshields are protected any time there are at least two sources of AC electrical power, and the probes are heated automatically whenever an engine is running or manually via a button on the FO's main panel.
There is some manual control of the system for abnormal operations and for takeoff. Although the mode selector is normally left on AUTO, turning it to ON manually activates engine and wing anti-ice (on engine start and liftoff, respectively). Individual selector buttons for the wings, each engine, and each windshield allow each component to be manually deactivated. These are seldom used except when components fail. Manual control of anti-ice systems for takeoff via the Flight Management System is much more common. Using bleed air robs the engine of compressed air for combustion and therefore use of wing and engine anti-ice results in decreased power output. For this reason, the JungleBus inhibits automatic operation of both wing and engine anti-ice until reaching 1700 feet AGL after takeoff. If anti-ice protection is desired for takeoff, the pilots must set it on the Takeoff Dataset Page of the Multi-Function Control Display Unit (MCDU, otherwise known as the FMS head). The standard mode, which inhibits anti-ice until 1700 feet AGL, is OFF. Turning it to ENG mode turns on engine anti-ice as soon as the engine is started. The ALL mode enables engine anti-ice on engine start and wing anti-ice when wheel speed exceeds 40 knots on takeoff. In both cases, the anti-ice systems revert to automatic operation once the plane reaches 1700 feet AGL.
At NewCo we turn the dataset to ENG mode if there is any precipitation falling or any surface contamination with a static air temperature of less than 10 degrees C, and we use ALL mode if there is visible moisture below 1700' AGL with a SAT of less than 5 degrees C. Of course we won't get any wing protection until achieving 40 knots on takeoff, so any prior contamination must be removed with de-ice fluid (Type I). This provides limited protection for active icing conditions on the ground (ie falling snow) so in many cases we follow application of de-ice fluid with a second coat of anti-ice fluid (Type IV). This is designed to absorb the falling precipitation and then shear off the wing during the takeoff roll, at which point the aircraft's own anti-ice systems will be protecting it.
Like most aircraft systems on the JungleBus, there is a dedicated synoptic page for the anti-ice system on the Multi Function Display (MFD). It displays the status of the bleed and anti-ice valves, pneumatic system pressures, and bleed air & wing duct temperatures. A color-coded schematic of the system makes it easier to quickly understand any abnormal conditions.
One annoyance of the JungleBus' ice protection system is that the ice detectors interact with the Stall Protection System with no provision for pilot intervention. Once ice is detected, the SPS will assume it remains on the airframe for the remainder of the flight and increase stick shaker & pusher speeds accordingly. This forces the pilots to use faster approach and landing speeds, which would be the correct thing to do anyways if the aircraft was actually loaded up with ice. It is, however, pretty ridiculous to be forced into using ice speeds to land in Dallas on a 90 degree day just because you picked up a trace of ice on climbout from Minneapolis several hours ago.
All in all, though, the JungleBus' ice protection system works pretty well. Last winter I had a few occasions where the ice built up pretty good on the windshield wiper before landing, and post-flight inspection revealed significant accumulation on unprotected surfaces but the heated portions of the wings and cowls remained absolutely clean. The aircraft handled quite well despite having a decent amount of ice on the nose, wing roots, and (gulp) tail. Really, the JungleBus' best ice-fighting technology is its thrust-to-weight ratio. Although transport category aircraft do have better equipment for dealing with ice than light aircraft, prudent airline pilots use it the same way as prudent private pilots: to keep ice accretion to minimum while exiting icing conditions ASAP. Being able to climb rapidly through icing layers means that the JungleBus' good ice protection comes in handy primarily when you find yourself stuck at a bad icing altitude for several minutes on approach.
We're supposed to get snow tonight so I think it won't be long before I put this knowledge to practical use. In my next post, I'll delve more deeply into de-icing ground procedures.
Thursday, October 30, 2008
OK, One More Ride
Hopefully you can indulge me one last motorcycle post before I return to our regularly scheduled aviation content; it turned out my riding season wasn't quite over yet.
The bike that we rode in the pictures from the last post is a 1988 BMW K75S. BMW K-Bikes, which include the K75, K100, K1, K1100, and K1200, are a series of sport-touring bikes featuring liquid-cooled inline engines that are famous for their durability. The first K-bike, the K100, was quite a departure from BMW's previous motorcycle designs when it was introduced in 1985; they'd built the brand on twin-cylinder horizontally opposed air-cooled motors not unlike small aircraft engines. The K100 was an instant hit. The next year, BMW introduced the K75, essentially identical to the K100 but with three cylinders instead of four, giving it a total displacement of 750 cc's instead of 1000 cc's. It was envisioned as a stripped-down, more affordable version of the K100. As the years went on, though, the K75 became even more popular than the K100. Its lighter weight gave it handling more on the sport side of "sport-touring," and the 3-cylinder engine was the smoothest motorcycle engine BMW (or arguably, any other manufacturer) ever produced. Today used K75s fetch a better price than K100s, but both are sought after and hold their value much better than other bikes their age.
The K75 pictured in the last post belongs to my brother Josiah. It used to belong to my dad, and it's the motorcycle I learned to ride on. I still ride it occasionally and always marvel at what a great bike it is, especially for one 20 years old. For the last year, I've kept my eye out for a good-priced K75 or K100. I like my little FZ600 but it's really designed for one thing, which it does very well: zipping around corners with one person on it. Touring is excruciating, as is riding 2-up (particularly for the passenger). When Dawn rode on the back of Josiah's K75 on our ride to Wisconsin, it was a revelation for her: this motorcycling thing is a lot more fun on a bike designed for 2-up touring! She indicated her openness to me buying a BMW. I kept an eye out, knowing the best deals are typically found in fall and winter.
Monday before last, I found a 1985 K100RS for sale in Aspen, Colorado, for a price significantly below bluebook. It had 64,000 miles on it, which would be a lot on most bikes but is actually average for BMWs this age; they've been known to last beyond 200,000 miles. I traded some emails with the owner, who indicated the bike had cosmetic issues but was mechanically sound. Unfortunately, I had to fly and wasn't able to get up to Aspen until [this past] Saturday afternoon; the owner already had someone coming to look at it Saturday morning. I told him to call me if they cancelled, and stashed a bag of riding & camping gear at the Minneapolis airport just in case.
Friday night, the owner called to tell me the other interested party had cancelled and I could come take a look if I wanted to. I jumpseated to Aspen via Denver on Saturday morning after I got off work. The bike was in better shape than I was expecting. After inspecting, riding, and buying the bike, I packed the included saddlebags and headed out around 3pm. I wanted to get to Denver that night, and was planning on taking US82 to I-70. The owner assured me that was the long way to Denver, and taking Independence Pass to Leadville would be much quicker. "The pass is clear," he told me.
A half hour later I yelped as the bike slipped and skidded out of control on a section of ice covered by wet snow. I eased off the throttle, concentrated on balancing while looking out at the road ahead, and somehow kept it upright until I rolled out of the shadows and back onto bare pavement. How horrible it would've been to drop the bike within my first hour of ownership! The pass wasn't remotely clear. There was snow and ice on every section not exposed to the sun. I was able to ride around most of it, and the rest I negotiated very carefully. Finally I reached the top, and with it a final sketchy section of ice with blowing snow on top. The road down the other side was perfectly clear; the ride to Leadville and then Denver was superb.
Sunday morning I set out from Denver at 7am. Denver itself was still surprisingly warm, but the eastern plains were chilled by a gusty north wind that grew more intense as I labored eastward. By the time I was 100 miles into Nebraska I was riding permanently heeled over, the gusts pushing me around in my lane. At 80 mph it was doable; every time I was forced to slow for traffic or construction the bike became increasingly hard to keep on the road. In Overton, 20 miles short of Kearney, I stopped for gas and had a tough time just riding an eighth of a mile at 30 mph. While at the service station a huge gust came up and nearly tipped my bike off the sidestand; more impressively, it visibly moved the gas pump. I checked the weather: Kearney was reporting gusts to 45, and Omaha was expecting gusts to 60. "This is nuts," I thought. I decided to quit for the day. Fortunately, there was a motel next to the gas station. Unfortunately, it was a near-exact replica of the Bates Motel, but in poorer repair. I survived by staying out of the shower; it was moldy, anyways.
Quitting early on Sunday left me nearly 600 miles from Minneapolis. I had hoped to be home Monday night; now I had doubts. The temperatures dipped well below freezing overnight; I contemplated a late departure and just trying for Des Moines before nightfall. Finally I decided to tough it out and simply stop often to warm up. It was 25 degrees F when I started riding at 7am on Monday morning. It was chilly enough just walking outside my motel room; it was incredibly cold at 70 mph. For the first several hours I stopped every 40 miles for coffee or to warm my hands under rest-stop hand dryers. By 10am, the temperature was above freezing and I was able to make good time. Between Omaha and Des Moines, it got up to a positively comfortable 41 degrees F. Once headed north on I-35, the temperatures started to drop again but by then I was on the home stretch and the cold didn't bother me as much. It was 35 degrees F when I rolled into Minneapolis at 5:30pm, having riden 580 miles for the day.
My new bike performed flawlessly. I was really impressed by its handling and comfort, not to mention relieved that it proved dependable. Dawn and I rode it a few nights ago (in balmy 40 degree weather!) and she likes it a lot too. Sadly I'll be putting the bike into storage for the winter this weekend; I think our Indian Summer is over and the cold is here to stay. The snow will be here before long; Minneapolis actually got flurries on Sunday. I've been reading our De-Ice Manual in cruise to get me back up to speed on those procedures; it's not going to be long before the deice pads of Minneapolis run red and green with glycol. Speaking of which, this seems likely a timely opportunity to discuss the JungleBus' de-ice/anti-ice systems. That'll be my next post. In the meantime I have one last short ride on Saturday before I put away the bikes and resign myself to the coming fury of the Minnesota winter.
The bike that we rode in the pictures from the last post is a 1988 BMW K75S. BMW K-Bikes, which include the K75, K100, K1, K1100, and K1200, are a series of sport-touring bikes featuring liquid-cooled inline engines that are famous for their durability. The first K-bike, the K100, was quite a departure from BMW's previous motorcycle designs when it was introduced in 1985; they'd built the brand on twin-cylinder horizontally opposed air-cooled motors not unlike small aircraft engines. The K100 was an instant hit. The next year, BMW introduced the K75, essentially identical to the K100 but with three cylinders instead of four, giving it a total displacement of 750 cc's instead of 1000 cc's. It was envisioned as a stripped-down, more affordable version of the K100. As the years went on, though, the K75 became even more popular than the K100. Its lighter weight gave it handling more on the sport side of "sport-touring," and the 3-cylinder engine was the smoothest motorcycle engine BMW (or arguably, any other manufacturer) ever produced. Today used K75s fetch a better price than K100s, but both are sought after and hold their value much better than other bikes their age.
The K75 pictured in the last post belongs to my brother Josiah. It used to belong to my dad, and it's the motorcycle I learned to ride on. I still ride it occasionally and always marvel at what a great bike it is, especially for one 20 years old. For the last year, I've kept my eye out for a good-priced K75 or K100. I like my little FZ600 but it's really designed for one thing, which it does very well: zipping around corners with one person on it. Touring is excruciating, as is riding 2-up (particularly for the passenger). When Dawn rode on the back of Josiah's K75 on our ride to Wisconsin, it was a revelation for her: this motorcycling thing is a lot more fun on a bike designed for 2-up touring! She indicated her openness to me buying a BMW. I kept an eye out, knowing the best deals are typically found in fall and winter.
Monday before last, I found a 1985 K100RS for sale in Aspen, Colorado, for a price significantly below bluebook. It had 64,000 miles on it, which would be a lot on most bikes but is actually average for BMWs this age; they've been known to last beyond 200,000 miles. I traded some emails with the owner, who indicated the bike had cosmetic issues but was mechanically sound. Unfortunately, I had to fly and wasn't able to get up to Aspen until [this past] Saturday afternoon; the owner already had someone coming to look at it Saturday morning. I told him to call me if they cancelled, and stashed a bag of riding & camping gear at the Minneapolis airport just in case.
Friday night, the owner called to tell me the other interested party had cancelled and I could come take a look if I wanted to. I jumpseated to Aspen via Denver on Saturday morning after I got off work. The bike was in better shape than I was expecting. After inspecting, riding, and buying the bike, I packed the included saddlebags and headed out around 3pm. I wanted to get to Denver that night, and was planning on taking US82 to I-70. The owner assured me that was the long way to Denver, and taking Independence Pass to Leadville would be much quicker. "The pass is clear," he told me.
A half hour later I yelped as the bike slipped and skidded out of control on a section of ice covered by wet snow. I eased off the throttle, concentrated on balancing while looking out at the road ahead, and somehow kept it upright until I rolled out of the shadows and back onto bare pavement. How horrible it would've been to drop the bike within my first hour of ownership! The pass wasn't remotely clear. There was snow and ice on every section not exposed to the sun. I was able to ride around most of it, and the rest I negotiated very carefully. Finally I reached the top, and with it a final sketchy section of ice with blowing snow on top. The road down the other side was perfectly clear; the ride to Leadville and then Denver was superb.
Sunday morning I set out from Denver at 7am. Denver itself was still surprisingly warm, but the eastern plains were chilled by a gusty north wind that grew more intense as I labored eastward. By the time I was 100 miles into Nebraska I was riding permanently heeled over, the gusts pushing me around in my lane. At 80 mph it was doable; every time I was forced to slow for traffic or construction the bike became increasingly hard to keep on the road. In Overton, 20 miles short of Kearney, I stopped for gas and had a tough time just riding an eighth of a mile at 30 mph. While at the service station a huge gust came up and nearly tipped my bike off the sidestand; more impressively, it visibly moved the gas pump. I checked the weather: Kearney was reporting gusts to 45, and Omaha was expecting gusts to 60. "This is nuts," I thought. I decided to quit for the day. Fortunately, there was a motel next to the gas station. Unfortunately, it was a near-exact replica of the Bates Motel, but in poorer repair. I survived by staying out of the shower; it was moldy, anyways.
Quitting early on Sunday left me nearly 600 miles from Minneapolis. I had hoped to be home Monday night; now I had doubts. The temperatures dipped well below freezing overnight; I contemplated a late departure and just trying for Des Moines before nightfall. Finally I decided to tough it out and simply stop often to warm up. It was 25 degrees F when I started riding at 7am on Monday morning. It was chilly enough just walking outside my motel room; it was incredibly cold at 70 mph. For the first several hours I stopped every 40 miles for coffee or to warm my hands under rest-stop hand dryers. By 10am, the temperature was above freezing and I was able to make good time. Between Omaha and Des Moines, it got up to a positively comfortable 41 degrees F. Once headed north on I-35, the temperatures started to drop again but by then I was on the home stretch and the cold didn't bother me as much. It was 35 degrees F when I rolled into Minneapolis at 5:30pm, having riden 580 miles for the day.
My new bike performed flawlessly. I was really impressed by its handling and comfort, not to mention relieved that it proved dependable. Dawn and I rode it a few nights ago (in balmy 40 degree weather!) and she likes it a lot too. Sadly I'll be putting the bike into storage for the winter this weekend; I think our Indian Summer is over and the cold is here to stay. The snow will be here before long; Minneapolis actually got flurries on Sunday. I've been reading our De-Ice Manual in cruise to get me back up to speed on those procedures; it's not going to be long before the deice pads of Minneapolis run red and green with glycol. Speaking of which, this seems likely a timely opportunity to discuss the JungleBus' de-ice/anti-ice systems. That'll be my next post. In the meantime I have one last short ride on Saturday before I put away the bikes and resign myself to the coming fury of the Minnesota winter.
Monday, October 20, 2008
October Ride
My one-week experience as a commuter made me glad that I don't do it full time, but it was entirely worth it to get the Saturday before last off. It was a beautiful autumn day in Minnesota, with clear skies and temperatures in the 70s. My dad and Dawn and I took advantage of the weather to get in one last motorcycle ride of the season, to southwest Wisconsin and back. My dad rode his BMW R1100, and I borrowed my brother's BMW K75 so Dawn could come along (my Yamaha has a tiny rear seat that limits two-up riding to short jaunts in town).
The 300 mile ride took us along the bluffs of the Mississippi River to Lake Pepin, through Wisconsin's hill country on twisting, roller-coaster back country roads, and back to the Twin Cities on a highway with fast sweeping curves through river valleys and hills. The fall colors weren't quite yet at peak but were still pretty spectacular at times. This is an area I fly over fairly often, and it's chock full of tantalizing-looking little twisty roads. It's too bad that our riding season is so short; I'm looking forward to next season so we can explore the area more.
Dawn took quite a few pictures from the back of my bike. Here are some of my favorites.
The 300 mile ride took us along the bluffs of the Mississippi River to Lake Pepin, through Wisconsin's hill country on twisting, roller-coaster back country roads, and back to the Twin Cities on a highway with fast sweeping curves through river valleys and hills. The fall colors weren't quite yet at peak but were still pretty spectacular at times. This is an area I fly over fairly often, and it's chock full of tantalizing-looking little twisty roads. It's too bad that our riding season is so short; I'm looking forward to next season so we can explore the area more.
Dawn took quite a few pictures from the back of my bike. Here are some of my favorites.
Tuesday, October 14, 2008
Commute to Work
If you arrive two hours before your flight as the airlines recommend - and you do, right? - it gives you plenty of time for people watching. Among the various subgroups of travelers you expect to find, there are almost always a few pilots standing around in uniform, often with pained expressions. Some of these may be "deadheading" - that is, being repositioned by their airline and getting paid for their time - but the majority are generally commuting to or from work on their own time. Commuting is the least favorite aspect of many pilots' lives, but is sometimes better than the alternative. The airline pilot's ability to live hundreds or even thousands of miles from his place of work is alternatively praised and bemoaned by those enduring the grind.
Very few airlines require their pilots to live at or near their domicile. They only require that pilots report for duty at the correct time and place; how to get there is up to the pilot. If you live in base, or within a hundred miles or so, you get to work just like everyone else: jump in your car (or as in my case, hop on the bus and train). Those who live outside driving distance are in the unique position of being able to fly to work, using their non-rev pass and jumpseating benefits. To an outsider, it all seems terribly convenient. After all, you could live anywhere in the world! What few realize is this travel is done on the pilot's own time, and is on a space-available basis. This adds considerably to the time and stress load of commuting.
The reasons that pilots commute to work are varied. For starters, airlines don't always put their hubs in places that pilots want to live. By its very nature, a hub will either be in a geographically central location ("flyover land") or one of the largest (and most expensive) coastal cities. Some people are happy to live in places like Detroit, Memphis, Newark, Houston, Dallas, Minneapolis, or Chicago - but some are not. Some people can afford to live in cities like San Francisco, Los Angeles, or New York - but many cannot, especially on junior FO pay. For these pilots, commuting is the key to living better or more affordably.
Other pilots have put down deep roots in a community and do not care to move simply because they got a new job. Many have young families they do not wish to uproot. Some have spouses that refuse to move. For these pilots, commuting is the key to a happier family life.
Finally, some pilots didn't intend to commute but that's the hand that life dealt them. Some airlines - regionals especially - are notorious for opening and closing bases at the drop of a hat. Some airlines, faced with financial trouble, have abruptly withdrawn from what was once a primary market and crew base (ie USAirways and Pittsburg). When faced with an unstable situation, it would be foolishness to move around regularly at the whims of the airline. For these pilots, commuting provides a measure of stability to their lives.
These are all situation where the ability to commute can improve a pilot's quality of life, but of course commuting exacts its own toll on quality of life. The decision to commute involves carefully calculating precisely which option sucks less. To begin with, commuting is enormously draining on your free time. The flight times involved are the very least of it. There's the time spent in airports waiting for flights and in hotel rooms or crashpads waiting for your trip to begin. Most airlines have a "commuter clause" in their contract that require you have two flights with seats available that arrive before your show time; depending on the flight loads and frequencies along your route, this could result in commuting into domicile many hours or even days before your trip. You generally can't count on jumpseats unless you're flying on your own airline and are fairly senior, or have an odd route with little competition from other commuters. Weather can further complicate things. This all assumes a single-leg commute; if you make it a multi-leg commute with a connection through a busy hub, the time wasted and stress caused increase exponentially.
Commuting can further decrease quality of life by forcing a pilot to bid solely on the basis of "commutability." To a commuter, the only criteria to judge a trip by is report time and release time. The commuter looks for a late report time, so they can commute to their domicile in the morning, and an early release time, so they can hopefully make it home that night. All the other things that pilots typically bid for - pay, productivity, time off, weekends off, lack of circadian swaps - are utterly secondary. Only when you are ultra-senior in your seat can you hope for a line that's both commutable and good.
Commuting can be expensive. When you're junior and unable to hold a "commutable" schedule, you end up spending a lot of nights at your domicile before and after trips. You either pay $40-80 per night for a crew rate at a nearby motel, or get a crashpad shared with other commuters for $150-300 a month. If you're an unfortunate soul condemned to commuting to reserve - the ninth circle of Commuter Hell - you'll end up spending a truly depressing amount of time in your crashpad. Avoiding this situation has caused many commuters to defer upgrades or transitions to better-paying equipment until they could hold a line, another major cost.
Given all this, it makes sense to avoid commuting if at all possible. One solution I've seen from many pilots is refreshingly old-fashioned: commute by car, like everyone else! You can live quite a ways from your base and make it work; after all, we're usually talking one roundtrip per week. For reserve, you'll need to be a two-hour drive away from the airport. Even the most wretched places to live generally have nice places 100 miles away. You could work in Newark and live in upstate New York; you could work in Detroit and live in Ann Arbor. Many pilots live near a small airport that has regional flights to their domicile; if the flight loads merit, they fly; otherwise they drive. It's a nice hybrid method that makes commuting more palatable.
I've managed to avoid commuting for the most part. My first few months at Horizon, I was living in LA while on reserve up in Portland. As commutes go this was an easy one: multiple direct flights to Portland from Burbank (which I lived next to) and LAX, as well as tons of easy connecting flights on Southwest. All the same, sitting on reserve in a crashpad away from home was tough, and Dawn didn't see me nearly as much as she'd like to. That plus our lack of roots in LA, the lower cost of living in Portland, and having friends in the Pacific Northwest made the decision to move an easy one. When I was hired at NewCo, we moved specifically for the MSP base. It was tough to leave the PNW but getting closer to family was important to us. While the townhouse was for sale, though, I traveled between Minneapolis and Portland enough to qualify as a semi-commuter; seeing the heavy loads on that route made me glad I wasn't doing it full time or long term.
I wrote most of this post Monday morning at gate F4 in Minneapolis, attempting to get to Detroit to start a trip. Minneapolis-Detroit is one of the toughest commutes in RedCo's system. Although there are frequent flights between the two hubs, they're often packed and there are literally hundreds of other commuters vying for a limited number of jumpseats. Many of NewCo's pilots have done this commute for a few months until their seniority can hold a Minneapolis base; fortunately I held MSP from the very start as both a FO and Captain. I'm commuting this week on a one-time basis as the result of a trip trade I did last week. I was originally scheduled to work this weekend, but then the weather reports started indicating that I was going to miss the best weekend of the autumn. My dad mentioned he wouldn't mind doing one last motorcycle ride of the season, so I found a Detroit trip starting on Monday to trade for my Minneapolis trip starting Saturday. I had a spectacular ride through southwest Wisconsin with my dad and Dawn on Saturday, but Monday I paid the piper. The flights were all oversold, prompting me to list for a 8:30am flight to make my 3:00pm report time. That flight went out with full passengers and all cockpit jumpseats and extra flight attendant jumpseats full, and I still had two standbys stranded above me on the list. The 10:05 flight was shaping up the same way, and my last-chance 11:25 flight was even more oversold. I was picking up my phone, getting ready to make my "commuter policy" call to crew scheduling and beg for a positive space seat on the 11:25, when the gate agent called my name. A seat had opened up! I grabbed my bags and trudged down the jetway to hunt down the last few remaining bits of overhead bin space. I sighed in relief that I made it on, and gave silent thanks that I don't have to do this every week.
Very few airlines require their pilots to live at or near their domicile. They only require that pilots report for duty at the correct time and place; how to get there is up to the pilot. If you live in base, or within a hundred miles or so, you get to work just like everyone else: jump in your car (or as in my case, hop on the bus and train). Those who live outside driving distance are in the unique position of being able to fly to work, using their non-rev pass and jumpseating benefits. To an outsider, it all seems terribly convenient. After all, you could live anywhere in the world! What few realize is this travel is done on the pilot's own time, and is on a space-available basis. This adds considerably to the time and stress load of commuting.
The reasons that pilots commute to work are varied. For starters, airlines don't always put their hubs in places that pilots want to live. By its very nature, a hub will either be in a geographically central location ("flyover land") or one of the largest (and most expensive) coastal cities. Some people are happy to live in places like Detroit, Memphis, Newark, Houston, Dallas, Minneapolis, or Chicago - but some are not. Some people can afford to live in cities like San Francisco, Los Angeles, or New York - but many cannot, especially on junior FO pay. For these pilots, commuting is the key to living better or more affordably.
Other pilots have put down deep roots in a community and do not care to move simply because they got a new job. Many have young families they do not wish to uproot. Some have spouses that refuse to move. For these pilots, commuting is the key to a happier family life.
Finally, some pilots didn't intend to commute but that's the hand that life dealt them. Some airlines - regionals especially - are notorious for opening and closing bases at the drop of a hat. Some airlines, faced with financial trouble, have abruptly withdrawn from what was once a primary market and crew base (ie USAirways and Pittsburg). When faced with an unstable situation, it would be foolishness to move around regularly at the whims of the airline. For these pilots, commuting provides a measure of stability to their lives.
These are all situation where the ability to commute can improve a pilot's quality of life, but of course commuting exacts its own toll on quality of life. The decision to commute involves carefully calculating precisely which option sucks less. To begin with, commuting is enormously draining on your free time. The flight times involved are the very least of it. There's the time spent in airports waiting for flights and in hotel rooms or crashpads waiting for your trip to begin. Most airlines have a "commuter clause" in their contract that require you have two flights with seats available that arrive before your show time; depending on the flight loads and frequencies along your route, this could result in commuting into domicile many hours or even days before your trip. You generally can't count on jumpseats unless you're flying on your own airline and are fairly senior, or have an odd route with little competition from other commuters. Weather can further complicate things. This all assumes a single-leg commute; if you make it a multi-leg commute with a connection through a busy hub, the time wasted and stress caused increase exponentially.
Commuting can further decrease quality of life by forcing a pilot to bid solely on the basis of "commutability." To a commuter, the only criteria to judge a trip by is report time and release time. The commuter looks for a late report time, so they can commute to their domicile in the morning, and an early release time, so they can hopefully make it home that night. All the other things that pilots typically bid for - pay, productivity, time off, weekends off, lack of circadian swaps - are utterly secondary. Only when you are ultra-senior in your seat can you hope for a line that's both commutable and good.
Commuting can be expensive. When you're junior and unable to hold a "commutable" schedule, you end up spending a lot of nights at your domicile before and after trips. You either pay $40-80 per night for a crew rate at a nearby motel, or get a crashpad shared with other commuters for $150-300 a month. If you're an unfortunate soul condemned to commuting to reserve - the ninth circle of Commuter Hell - you'll end up spending a truly depressing amount of time in your crashpad. Avoiding this situation has caused many commuters to defer upgrades or transitions to better-paying equipment until they could hold a line, another major cost.
Given all this, it makes sense to avoid commuting if at all possible. One solution I've seen from many pilots is refreshingly old-fashioned: commute by car, like everyone else! You can live quite a ways from your base and make it work; after all, we're usually talking one roundtrip per week. For reserve, you'll need to be a two-hour drive away from the airport. Even the most wretched places to live generally have nice places 100 miles away. You could work in Newark and live in upstate New York; you could work in Detroit and live in Ann Arbor. Many pilots live near a small airport that has regional flights to their domicile; if the flight loads merit, they fly; otherwise they drive. It's a nice hybrid method that makes commuting more palatable.
I've managed to avoid commuting for the most part. My first few months at Horizon, I was living in LA while on reserve up in Portland. As commutes go this was an easy one: multiple direct flights to Portland from Burbank (which I lived next to) and LAX, as well as tons of easy connecting flights on Southwest. All the same, sitting on reserve in a crashpad away from home was tough, and Dawn didn't see me nearly as much as she'd like to. That plus our lack of roots in LA, the lower cost of living in Portland, and having friends in the Pacific Northwest made the decision to move an easy one. When I was hired at NewCo, we moved specifically for the MSP base. It was tough to leave the PNW but getting closer to family was important to us. While the townhouse was for sale, though, I traveled between Minneapolis and Portland enough to qualify as a semi-commuter; seeing the heavy loads on that route made me glad I wasn't doing it full time or long term.
I wrote most of this post Monday morning at gate F4 in Minneapolis, attempting to get to Detroit to start a trip. Minneapolis-Detroit is one of the toughest commutes in RedCo's system. Although there are frequent flights between the two hubs, they're often packed and there are literally hundreds of other commuters vying for a limited number of jumpseats. Many of NewCo's pilots have done this commute for a few months until their seniority can hold a Minneapolis base; fortunately I held MSP from the very start as both a FO and Captain. I'm commuting this week on a one-time basis as the result of a trip trade I did last week. I was originally scheduled to work this weekend, but then the weather reports started indicating that I was going to miss the best weekend of the autumn. My dad mentioned he wouldn't mind doing one last motorcycle ride of the season, so I found a Detroit trip starting on Monday to trade for my Minneapolis trip starting Saturday. I had a spectacular ride through southwest Wisconsin with my dad and Dawn on Saturday, but Monday I paid the piper. The flights were all oversold, prompting me to list for a 8:30am flight to make my 3:00pm report time. That flight went out with full passengers and all cockpit jumpseats and extra flight attendant jumpseats full, and I still had two standbys stranded above me on the list. The 10:05 flight was shaping up the same way, and my last-chance 11:25 flight was even more oversold. I was picking up my phone, getting ready to make my "commuter policy" call to crew scheduling and beg for a positive space seat on the 11:25, when the gate agent called my name. A seat had opened up! I grabbed my bags and trudged down the jetway to hunt down the last few remaining bits of overhead bin space. I sighed in relief that I made it on, and gave silent thanks that I don't have to do this every week.
Sunday, October 12, 2008
JungleBus Systems Post: Hydraulics
I've mentioned a few times that NewCo's initial training program was a bit, ahem, basic, and that I felt somewhat underprepared in the area of systems knowledge when I first got on the line. Since then I've gone back and studied on my own a few times, but I still feel like I could benefit from a more intimate knowledge of JungleBus systems. In my experience, the best way to learn aviation knowledge is to teach it. With that in mind, I'll be writing occasionally posts on various JungleBus systems. They won't be in any particular order; today I've randomly chosen to begin with a dissertation on the Hydraulic System. Those with JungleBus experience are welcomed to add anything I forget or correct my mistakes. I hope that by next time I have recurrent ground school, I have a nice collection of posts to come back and read rather than poring through AOM-II for hours on end until my eyes bug out.
On most light planes, the hydraulic system is limited to powering the brakes and, in some cases, retractible landing gear. Once you get to airliner weights, though, you find that the forces involved often outstrip the ability of the human muscle to overpower. In these cases, engineers rely on hydraulic systems to do the grunt work. This is the case with many systems on the JungleBus, including all basic flight controls, spoilers, landing gear, brakes, nosewheel steering, and thrust reverser deployment. Notably missing are the flaps, which are hydraulically powered on many airliners but are electric on the JungleBus.
Hydraulic systems use a fluid under pressure to do work. This is possible because fluids are mostly incompressible. For a hydraulic system to work, you need a source of pressure (a pump), a closed system that remains leak-free under significant pressure, and enough fluid to pressurize the system to design pressure. Hydraulic systems have a number of failure nodes: pump failure, loss of power to the pump, loss of fluid, and physical damage to the plumbing so it's unable to hold pressure. For these reasons, aircraft engineers build multiple independent hydraulic systems into the airliners they design, usually with multiple sources of power for each system.
The JungleBus has three fully independent hydraulic systems. Systems 1 and 2 are normally pressurized by engine-driven pumps (EDPs), which are connected to their respective engine's accessory gearbox. They each have an electric hydraulic pump installed as backup in case of engine failure. System 3 is powered solely by an electric pump, with a second electric pump as backup. All three systems use Skydrol brand hydraulic fluid and are normally pressurized to 3000 psi. Most aircraft systems that use hydraulic power are powered by at least two of these systems, so the loss of one hydraulic system will not affect most other aircraft systems. Flight critical systems are powered by three systems, so in the highly unlikely event of two fully independent systems failing simultaneously, the crew will still have at least pitch and roll control.
Hydraulic System 1 is normally pressurized by a mechanical pump driven by the left engine's accessory gearbox. The pump takes fluid from the reservoir, which an accumulator keeps at slight positive pressure, and pressurizes the fluid before sending it through a filter and the plumbing to the various System 1 users. The return line routes the fluid through another filter and then either through a heat exchanger or directly to the reservoir, depending on fluid temperature. If the fluid reaches 100º C, a HYD 1 HI TEMP caution message is displayed on the EICAS. At 125º C, the Hydraulic Shutoff Valve (HSOV) automatically closes to isolate EDP 1 from System 1. The HSOV will also close automatically in case of engine failure to decrease drag on the engine and make a windmilling relight easier. The HSOV can also be closed manually via a guarded push button on the hydraulic panel.
In case of engine failure or EDP failure, System 1 can be pressured by Electric Hydraulic Pump 1, powered by alternating current from AC BUS 2. It is controlled by a 3-position switch on the hydraulic panel. With the switch OFF, the pump stays off; selecting ON causes the pump to run continuously regardless of conditions. The normal position is AUTO, which causes the pump to activate automatically in case of engine 1 failure or EDP failure. In AUTO mode, the electric hydraulic pump will also run concurrently with the EDP when the flaps are in any position greater than zero in flight, or on the ground when flaps are greater than zero and thrust levers are in takeoff/goaround position (TOGA) or groundspeed exceeds 50 kts. The idea is to have both engine-driven and electric pumps running during takeoff and landing.
Hydraulic System 1 has the following users:
System 1 and 2 don't have any common points where fluid can migrate, but there is a mechanical connection via the Power Transfer Unit, or PTU. This is basically an extra pump used to pressurize part of System 2; it is motored by hydraulic pressure in System 1. The only purpose of the PTU is to facilitate extension and retraction of the landing gear. To operate, it needs System 1 to be pressurized, and there must be fluid in System 2. It is controlled by a 3-position "OFF-AUTO-ON" knob, which is almost always left in AUTO. In this position, system logic will turn on the PTU if the right engine or EDP 2 fails when the flaps are greater than zero. It's essentially there to quickly raise the landing gear if the right engine fails just after takeoff and Electric Hyd Pump 2 fails or isn't supplying enough pressure to the landing gear. Note that the PTU is useless to raise or extend the landing gear in case of System 2 fluid loss; in this case the crew must extend the gear using a freefall procedure. There is no way to retract the gear with no fluid in System 2.
Hydraulic System 3 is essentially an emergency backup system to ensure critical flight controls remain powered in case of a catastrophic simultaneous failure of Systems 1 and 2. It is pressurized by one electric pump (Electric Hyd Pump 3A) with an additional electric pump (Electric Hyd Pump 3B) for backup. Pump 3A is controlled by an OFF-ON knob on the hydraulic panel, with no automation involved. It gets its power from the AC ESS bus, which remains powered in an electrical emergency. Pump 3B has a 3-position OFF-AUTO-ON knob; in AUTO position it will activate whenever Pump 3A fails. Pump 3B is powered by AC BUS 2. System 3 powers the following hydraulic users:
The Multi-Function Display (MFD) in the flight deck can bring up a Hydraulic Synoptic Page. It displays hydraulic fluid quantity, temperature, and pressure for all three systems and shows the status of all engine-driven and electric hydraulic pumps, plus the PTU. Finally, the Synoptic Page displays a handy list of all hydraulic users, organized by system. This, in case of hydraulic system failure, the pilots can see at a glance which aircraft systems will be affected.
You can see that the JungleBus could suffer multiple hydraulic failures and the most critical systems will be unaffected. Either engine failure should not affect any of the three systems. Complete System 1 failure would leave the pilots with three of four elevator actuators, all four aileron actuators, one of two rudder actuators, two of six roll spoilers, two of four ground spoilers, one of the two thrust reversers, and two of four brakes. Complete System 2 failure would still leave powered two of four elevator actuators, two of four aileron actuators, both rudder actuators, four of six roll spoilers, two of four ground spoilers, one thrust reverser, and two of four brakes. A combined System 2 + System 3 failure would leave the ailerons unpowered but you'd still have one rudder actuator and four of six roll spoilers for roll control. The only catastrophic combination, of course, is an uncontained engine failure or similarly violent event that results in failure of all three systems a la United 232. Of course, certification standards have improved considerably since then to ensure the physical separation and protection of hydraulic system components. That's good because, despite its smaller size, the JungleBus is just as dependent on hydraulics as the DC-10.
On most light planes, the hydraulic system is limited to powering the brakes and, in some cases, retractible landing gear. Once you get to airliner weights, though, you find that the forces involved often outstrip the ability of the human muscle to overpower. In these cases, engineers rely on hydraulic systems to do the grunt work. This is the case with many systems on the JungleBus, including all basic flight controls, spoilers, landing gear, brakes, nosewheel steering, and thrust reverser deployment. Notably missing are the flaps, which are hydraulically powered on many airliners but are electric on the JungleBus.
Hydraulic systems use a fluid under pressure to do work. This is possible because fluids are mostly incompressible. For a hydraulic system to work, you need a source of pressure (a pump), a closed system that remains leak-free under significant pressure, and enough fluid to pressurize the system to design pressure. Hydraulic systems have a number of failure nodes: pump failure, loss of power to the pump, loss of fluid, and physical damage to the plumbing so it's unable to hold pressure. For these reasons, aircraft engineers build multiple independent hydraulic systems into the airliners they design, usually with multiple sources of power for each system.
The JungleBus has three fully independent hydraulic systems. Systems 1 and 2 are normally pressurized by engine-driven pumps (EDPs), which are connected to their respective engine's accessory gearbox. They each have an electric hydraulic pump installed as backup in case of engine failure. System 3 is powered solely by an electric pump, with a second electric pump as backup. All three systems use Skydrol brand hydraulic fluid and are normally pressurized to 3000 psi. Most aircraft systems that use hydraulic power are powered by at least two of these systems, so the loss of one hydraulic system will not affect most other aircraft systems. Flight critical systems are powered by three systems, so in the highly unlikely event of two fully independent systems failing simultaneously, the crew will still have at least pitch and roll control.
Hydraulic System 1 is normally pressurized by a mechanical pump driven by the left engine's accessory gearbox. The pump takes fluid from the reservoir, which an accumulator keeps at slight positive pressure, and pressurizes the fluid before sending it through a filter and the plumbing to the various System 1 users. The return line routes the fluid through another filter and then either through a heat exchanger or directly to the reservoir, depending on fluid temperature. If the fluid reaches 100º C, a HYD 1 HI TEMP caution message is displayed on the EICAS. At 125º C, the Hydraulic Shutoff Valve (HSOV) automatically closes to isolate EDP 1 from System 1. The HSOV will also close automatically in case of engine failure to decrease drag on the engine and make a windmilling relight easier. The HSOV can also be closed manually via a guarded push button on the hydraulic panel.
In case of engine failure or EDP failure, System 1 can be pressured by Electric Hydraulic Pump 1, powered by alternating current from AC BUS 2. It is controlled by a 3-position switch on the hydraulic panel. With the switch OFF, the pump stays off; selecting ON causes the pump to run continuously regardless of conditions. The normal position is AUTO, which causes the pump to activate automatically in case of engine 1 failure or EDP failure. In AUTO mode, the electric hydraulic pump will also run concurrently with the EDP when the flaps are in any position greater than zero in flight, or on the ground when flaps are greater than zero and thrust levers are in takeoff/goaround position (TOGA) or groundspeed exceeds 50 kts. The idea is to have both engine-driven and electric pumps running during takeoff and landing.
Hydraulic System 1 has the following users:
- Elevator (Left-Hand outboard actuator only)
- Rudder (upper actuator)
- Spoilers (LH & RH, panels 2, 3, and 4)
- Thrust Reverser (Engine 1)
- Brakes (outboard only)
- Emergency/Parking Brake
- Elevators (LH & RH inboard actuators)
- Ailerons (LH & RH inboard actuators)
- Spoilers (LH & RH, panels 1 and 5)
- Thrust Reverser (Engine 2)
- Brakes (inboard only)
- Nosewheel Steering
- Landing Gear
- Emergency/Parking Brake
System 1 and 2 don't have any common points where fluid can migrate, but there is a mechanical connection via the Power Transfer Unit, or PTU. This is basically an extra pump used to pressurize part of System 2; it is motored by hydraulic pressure in System 1. The only purpose of the PTU is to facilitate extension and retraction of the landing gear. To operate, it needs System 1 to be pressurized, and there must be fluid in System 2. It is controlled by a 3-position "OFF-AUTO-ON" knob, which is almost always left in AUTO. In this position, system logic will turn on the PTU if the right engine or EDP 2 fails when the flaps are greater than zero. It's essentially there to quickly raise the landing gear if the right engine fails just after takeoff and Electric Hyd Pump 2 fails or isn't supplying enough pressure to the landing gear. Note that the PTU is useless to raise or extend the landing gear in case of System 2 fluid loss; in this case the crew must extend the gear using a freefall procedure. There is no way to retract the gear with no fluid in System 2.
Hydraulic System 3 is essentially an emergency backup system to ensure critical flight controls remain powered in case of a catastrophic simultaneous failure of Systems 1 and 2. It is pressurized by one electric pump (Electric Hyd Pump 3A) with an additional electric pump (Electric Hyd Pump 3B) for backup. Pump 3A is controlled by an OFF-ON knob on the hydraulic panel, with no automation involved. It gets its power from the AC ESS bus, which remains powered in an electrical emergency. Pump 3B has a 3-position OFF-AUTO-ON knob; in AUTO position it will activate whenever Pump 3A fails. Pump 3B is powered by AC BUS 2. System 3 powers the following hydraulic users:
- Elevator (RH outboard actuators)
- Rudder (lower actuator)
- Ailerons (LH & RH outboard actuators)
The Multi-Function Display (MFD) in the flight deck can bring up a Hydraulic Synoptic Page. It displays hydraulic fluid quantity, temperature, and pressure for all three systems and shows the status of all engine-driven and electric hydraulic pumps, plus the PTU. Finally, the Synoptic Page displays a handy list of all hydraulic users, organized by system. This, in case of hydraulic system failure, the pilots can see at a glance which aircraft systems will be affected.
You can see that the JungleBus could suffer multiple hydraulic failures and the most critical systems will be unaffected. Either engine failure should not affect any of the three systems. Complete System 1 failure would leave the pilots with three of four elevator actuators, all four aileron actuators, one of two rudder actuators, two of six roll spoilers, two of four ground spoilers, one of the two thrust reversers, and two of four brakes. Complete System 2 failure would still leave powered two of four elevator actuators, two of four aileron actuators, both rudder actuators, four of six roll spoilers, two of four ground spoilers, one thrust reverser, and two of four brakes. A combined System 2 + System 3 failure would leave the ailerons unpowered but you'd still have one rudder actuator and four of six roll spoilers for roll control. The only catastrophic combination, of course, is an uncontained engine failure or similarly violent event that results in failure of all three systems a la United 232. Of course, certification standards have improved considerably since then to ensure the physical separation and protection of hydraulic system components. That's good because, despite its smaller size, the JungleBus is just as dependent on hydraulics as the DC-10.
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